Novolac alkylphenol resins, method of production thereof and use thereof as tackifying and/or reinforcing resins for rubbers

ABSTRACT

The invention relates to novolac alkylphenol resins having a low level of free alkylphenol, a method for the production thereof, and the use thereof as tackifying resins and reinforcing resins for rubbers. The resins may be used advantageously in the production of tires.

This application claims priority to International Application No.PCT/FR2004/002495, filed Oct. 1, 2004, which claims priority to FrenchApplication No. 0311606, filed Oct. 3, 2003, both of which are hereinincorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to novolac alkylphenol resins used thatcan be used for tackifying resins or reinforcing resins for rubbercompositions.

BACKGROUND

Novolac alkylphenol resins may be obtained by reacting alkylphenols suchas para-tertiary butylphenol (PTBP) and para-tertiary octylphenol (PTOP)with aldehydes, especially formaldehyde, in the presence of acidcatalysts. See Knop et al., “Chemistry and application of phenolicresins,” Polymer/properties and Application, ed. Springer-Verlag BerlinHeidelberg New York, p. 10-27 (1979), which gives an overview of thedifferent aldehydes and alkylphenol monomers used in the novolacalkylphenol phenolic resins.

It is known that by varying the molar ratio (MR) ofaldehydes(s)/alkylphenol(s), it is possible to prepare resins havingdifferent average molecular masses. However, due to the chemical natureof the reaction, a fraction of free phenolic monomers remains after theformaldehyde has been consumed at the end of the reaction. An estimationof the fraction of free phenols has been calculated by considering theformaldehyde/phenol as a statistical polycondensation. See Borrajo etal., Polymer, Vol. 23, February, p. 263-266 (1982). Borrajo et al.discuss that, according to Stokemayer's distribution, a reaction carriedout with MR 0.7 yields a rate of residual phenol of 11.6%, a MR of 0.8yields 6.5%, and a MR of 0.9 yields 3%; the calculation also describesMRs of 9, 4 and 1%, respectively, for a difunctional paraalkylphenol.Typically, the molar ratio used for production of commercial novolacalkylphenol resins varies from 0.7 to 0.9.

It is desirable to reduce this rate of residual phenolic monomer(s) forenvironmental reasons, on one hand, and to diminish the nature ofdangers of resins. In fact, alkylphenols like PTOP are the object ofenvironmental and toxicology studies (risk assessment studies) to limittheir use in the free monomer form in novolac alkylphenol resins. Thedecrease in the free alkylphenol rate also permits a simplermanipulation of resins by decreasing the vapor emissions ofalkylphenolic monomers in factories or in atmospheric discharges whenthey are used, in particular rubber applications when vulcanization iscarried out at elevated temperature.

The commercial novolac alkylphenol resins used as tackifying resins inthe formulation of rubber generally have a softening point temperaturebetween 85 and 105° C. Since the usage temperature are dictated bycomplex components of the rubber-based formulations and cannot bemodified easily without changing the reactivity of the system: thealkylphenolic resins in this softening point temperature range aresuitable for allowing the dissolution, the fusion and the dispersion ofthe resin during its mixing step with the other components of the rubberformulation and at the time of the vulcanizing step.

Wolny et al., Kautsuch Gummi Kunstoffe [Rubber, Plastics] 37:7, p.601-603 (1984) describes novolac resins from the condensation of thePTOP and formaldehyde that have a temperature close to 100° C. and havea residual free alkylphenol rate of about 4.5%. The MR, however, isabout 0.8 to 0.9, and the resins have a softening point value of 85-110°C. A rate of free residual PTOP less than 1% could not be obtainedwithout having a MR greater than 0.9 with a softening point temperatureof around 120° C. For a novolac PTOP/formol resin with MR 0.96, the rateof free PTOP is less than 1% and the softening point temperature iselevated (around 130-140° C.). In addition to the elevated temperatures(around 180° C.), the synthesis is delicate because of the significantviscosity of the resin. For resins with PTBP having high softening pointtemperatures (on the order of 120-130° C.) and a MR on the order of 0.8,the residual PTBP rate is observed to be around 2 to 3%.

The free residual monomer or monomers can be distilled at the end of theresin synthesis to decrease the rate of free alkylphenols. However, thisconventional method presents several disadvantages: first, thedistillation of the free monomer or monomers represents a notinsignificant loss of primary material and requires recycling ortreatment of the distilled alkylphenol; second, it is difficult toimplement at the industrial level for the alkylphenols like PTOP thathave very high boiling points, which involves a very powerful vacuum andelevated temperatures in the reactor in order. Besides that,alkylphenols that are solid compounds, like PTBP and PTOP, crystallizein the piping which requires reheating if plugs are to be prevented.

U.S. Pat. No. 6,326,453 and EP 1,108,734 A1 teach that the reduction inthe rate of free phenol in novolac (alkyl)phenol resins can also beobtained by the use of an organophosphonic catalyst. However, asignificant amount of catalyst is used. To arrive at a rate of residualfree phenol less than 1%, it is necessary to use 60% by weight oforganophosphonic catalyst, based on the weight of the phenol, and for arate of residual phenol of around 2%, it is necessary to use 10% byweight of catalyst. These references also indicated that as the rate ofcatalyst becomes lower, with 0.1 mol-% in comparison to the phenol, thereaction becomes ineffective.

JP1-349.655 describes the preparation of novolac phenol-formol resins ina methanol solution under supercritical conditions of 15 MPa/250° C. toobtain a rate of free phenol of 1%. This type of procedure is verydifficult to implement on the industrial level because of the elevatedpressures necessary, as it is preferable to work at pressures close toatmospheric pressure.

The addition of urea is recommended by Li Ziqiang, Mining & Metallurgy,Vol. 5, No. 1, p. 24-27 (March 1996) (CAS 125:115938). According to theZiqiang, this makes it possible to decrease the free phenol from 18%(without urea) to 5%. But this is still too high. Besides that, theintroduction of urea into the product involves the risk of deterioratingthe stability of the phenolic resin and thus negatively effecting thefinal properties of the resulting rubber formulations.

CS 238.995 (CAS 108:57118) describes the preparation of a mixture madeup of phenol, formaldehyde (MR 0.97), and stearic acid (3.5% by weightbased on the phenol) in the presence of various additives or batches.The resin obtained after reaction of the mixture has a rate of freephenol of 5%.

U.S. Pat. No. 2,506,903 and U.S. Pat. No. 2,506,904 teach thepreparation of greases (which have a softening point value that is closeto or less than the ambient temperature) obtained by esterification of anovolac formophenolic resin with fatty acids, the formol/alkylphenolratio MR described in the application varies from 1 to 2. Thepreparation process consists either of (a) esterifying the alkyl phenolwith the fatty acid near 100° C., which is reacted with formaldehyde attemperatures up to 250° C., or (b) preparing theformaldehyde/alkylphenol resin at a temperature of 100-150° C., then toadding fatty acid to carry out the esterification reaction at atemperature of 200° C. The rate of fatty acid necessary to obtain aproduct in the form of grease is on the order of 100% of the alkylphenolmass used.

JP09-003.384 (CA/126:187493) describes the modification byesterification of a formophenolic resin of the resol type (prepared witha base catalysis) at a temperature greater than 200° C., typicallybetween 200 and 260° C., with a fatty acid in the presence of rosin orone of its derivatives. The rate of residual phenolic monomer is lessthan or equal to 1%. This modified resin being used for the manufactureof printing ink.

Accordingly, no satisfying technical solution exists for decreasing therate of residual alkylphenol(s) in the novolac alkylphenol resins below2% while maintaining a softening point temperature between 85 and 105°C., so that the resins can be used as tackifying or reinforcing resinsin rubber-based formulations. This invention answers that need.

SUMMARY OF THE INVENTION

One embodiment of the invention relates to a novolac alkylphenol resin,comprising 2-20% by weight based on the weight of the alkylphenol, of atleast one saturated or unsaturated fatty acid. The resin has a rate ofresidual alkylphenol of less than 2% and a softening point temperaturebetween 85-105° C.

Another embodiment of the invention relates to a process for preparing anovolac alkylphenol resin. The process includes (a) reacting analkylphenol with an aldehyde to form a first resin, wherein the molarratio of the alkylphenol:aldehyde is at least 0.9:1.0, and (b) mixingthe first resin with at least one saturated or unsaturated fatty acid ina melted state, to form a novolac alkylphenol resin. The novolacalkylphenol resin has a residual alkylphenol of less than 2% and asoftening point temperature between 85-105° C.

Another embodiment of the invention relates to a process for thepreparing a novolac alkylphenol resin. The process includes condensingan aldehyde and an alkylphenol in the presence of at least one saturatedor unsaturated fatty acid at a temperature of less than or equal to 200°C., to form a novolac alkylphenol resin. The novolac alkylphenol resinhas a residual alkylphenol of less than 2% and a softening pointtemperature between 85-105° C.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a tack measurement assembly diagram.

FIG. 2 is a graph illustrating the force as a function of displacement,time, and tack measurement.

DETAILED DESCRIPTION

An object of the invention is to produce a novolac alkylphenol resinhaving a residual rate of alkylphenol(s) of less than 2%, preferablyless than or equal to 1.5%, and most preferably less than or equal to 1%while having a softening point temperature between 85 and 105° C.,preferably between 95 and 105° C. The resins may be obtained using oneor several alkylphenolic monomers, one or several aldehydes, and 2 to20%, more preferably 5 to 10%, by weight based on the alkylphenol(s), ofat least one saturated or unsaturated fatty acid.

The alkylphenols are phenols, preferably alkylated with ahydrocarbonated alkyl group in para position of the phenol group andhaving 6 to 10 carbon atoms. The use of a tertioctyl alkyl group, suchas para-tertiary octylphenol, is the most preferred. In addition to thealkylphenolic monomers described above, the novolac resins can alsocontain other phenols. These other phenols can represent up to 30% ofthe total mass of the phenols of the resin. Suitable other phenolsinclude phenol, resorcinol, cardanol, and dialkylphenols, such asdimethylphenols, xylenols, or 2,4 or 2,6-ditertiary octylphenols.

Any aldehyde is suitable. Preferably, the aldehyde is formol orformaldehyde.

The fatty acids may be saturated mono-carboxylic acids or mono-olefinicshaving at least 8 carbon atoms. Preferably, the saturated fatty acidshave 8 to 32 carbon atoms. Suitable saturated fatty acids includecaprylic, pelargonic, capric, undecylic, lauric, stearic and behenicacid. Suitable unsaturated fatty acids include oleic and undecylicacids. It is also possible to use synthetic or natural mixtures of thesefatty acids, which can be obtained by saponification of vegetable oilsor animal fats. Stearic acid is especially preferred.

Another object of the invention relates to a process for preparing anovolac alkylphenol resins. For the resins that contain formol, theformol is usually introduced into the reaction medium in the form of anaqueous solution; it can also be introduced in the form ofparaformaldehyde.

The novolac resin can be prepared by synthesizing formophenolic resinsof the novolac type with aldehydes/alkylphenol having a molar ratiogreater than 0.9. A first resin with elevated softening pointtemperature (i.e. greater than 110° C.) is formed. The fatty acid oracids are then added while the resin is again in a melted state. Theresin may be melted, either in the synthesis reactor or in the presenceof the fatty acid or acids, which are agitated in order to mix it/themwith in the resin in a homogeneous manner.

Alternatively, the condensation of the aldehydes or aldehydes may becarried out with the alkylphenol(s) in the presence of the fatty acid(s)at temperatures less than or equal to 200° C., preferably less than orequal to 180° C., most preferably less than or equal to 160° C. Thepreparation of the resin in a single step offers several advantages incomparison to the procedure described above, where the alkylphenol(s)and aldehydes(s) are condensed before being mixed with the fattyacid(s). First, the formation of a reaction medium with elevatedviscosity in the reactor at the time of synthesis of the novolac resinis avoided or reduced. Second, the use of elevated temperature that isotherwise required or desirable in conventional techniques can also beavoided.

The preferred procedure described above can either be a procedure of thebatch type or a continuous procedure in which alkylphenol(s), fattyacid(s) and aldehydes(s) are introduced continuously into the reactor orinto a series of reactors. A description of continuous procedures can befound in Knop et al., “Chemistry and application of phenolic resins,”Polymer/properties and Application, ed. Springer-Verlag BerlinHeidelberg, New York, p. 62-64 (1979), herein incorporated by referencein its entirety.

In general, the process may be carried out by introducing alkylphenol(s)and fatty acid(s) into the reactors, followed by the acid catalyst orcatalysts into the reactors; the mixture is then brought to 80-100° C.at atmospheric pressure and the aldehydes or aldehydes are introduced toflow in over a period that varies from 15 to 100 minutes, the mixturebeing kept under agitation. When the aldehyde is formol, preferably asolution of formaldehyde in water is used and the medium is held atreflux until the formaldehyde is finished flowing in.

After the aldehyde or aldehydes have flowed in, the temperature of themedium is raised to 120-150° C. in order to distill the reaction waterand any water that has been introduced with the aldehydes. The reactoris then placed under a slight vacuum (pressure of 0.2 to 0.6 bar,absolute) and a temperature of 140-160° C. for a period that cantypically vary from around 30 to 400 minutes, depending on the size ofthe reactor used and the equipment used to produce the vacuum. Thetracking of the softening point temperature value during this periodmakes it possible to determine the stopping point of the resin. It isthen possible to add a base like sodium carbonate, soda, or amines, forexample triethanolamine, to neutralize the catalyst. The addition of abase is not obligatory but makes it possible to better control thedevelopment of the resin in the reactor. The reactor is then dischargedand the resin is obtained.

The catalysts used for synthesis of novolac resins may be any acidcatalysts known to the person skilled in the art. Suitable catalystsinclude mineral or organic acids, alone or in a mixture, sulfuric acidthat is pure or in solution in alcoholic solvents, phosphoric acid,oxalic acid or formic acid. The catalyst quantities used generally varyfrom 0.4 to 0.1%, based on the mass of alkylphenol(s).

Another object of the invention relates to the use of compounds astackifying resins in the formulation in rubber. The novolac resins ofthe invention present the advantage of requiring little to nomodification of the application conditions of the rubber formulation inwhich they are incorporated. Yet the resins remain as effective asconventional resins and have a lower rate of free alkylphenol monomers,thus a reduced emission of harmful alkylphenol compounds when they areused.

EXAMPLES

The following examples illustrate the invention

Determination of the Rate of Free Alkylphenol(s)

The determination of the rate of residual PTOP is carried out usingvapor phases chromatography on a Hewlett Packard 5890 Series IIchromatograph equipped with an injector/divider, a CPV column, an FIDdetector and a recorder/integrator. The column is an OV1701® from OHYOVALLEY (length 30 m, internal diameter 0.25 mm, film thickness 0.25 μm).The measurement is carried out isothermically at 180° C., the period ofanalysis is 25 min. The injector temperature is 250° C., detector: 250°C. In a 10 ml bottle, about 0.03 g of reference standard BHT(2,6-di-tert-butyl-4-methylphenol) is weighed in, then about 1 g resinand finished with about 6 g RP acetone. The response coefficient isdetermined by injecting a PTOP/BHT standard under the same dilutionconditions.

Measurement of the Softening Point Value

This measurement is carried out according to standard E28-96 on an NBA440® or NBA 430 device from the NORMALAB Company.

Operating Method for Examples 1 to 8 (Comparative) and Examples 9 to 11(According to the Invention)

500 g para-tertiary octylphenol and possible X g of stearic acid (Table1 gives the quantity of stearic acid added as a percentage of the PTOPintroduced) and 2.1 g catalyst (sulfuric acid solution at 25% inisopropyl alcohol) is added to a 1 liter glass reactor equipped with amechanical agitator and a refrigerant system in order to ensure anefficient reflux. The temperature of the medium is raised to 90° C.while agitating. The formaldehyde solution at 50% in water is maintainedat 60° C. and then allowed to flow in over a period of 30 to 45 minutes,while regulating the flow of formaldehyde in such a way as to maintain atemperature of 100-110° C. in the reactor. When the formaldehyde isfinished flowing in, the assembly is modified in order to permit thedistillation of the reaction water. Then the temperature of the reactionmedium is raised progressively toward 130-150° C. (T1 in Table 1) whiledistilling the water of the medium. This first phase lasts around one totwo hours. The medium becomes thicker and foamy. When no more distillateremains, the temperature of the medium is raised progressively toward150° C. while decreasing the pressure to 0.4 bar absolute to finish theremoval of the water in the medium (i.e. the values T2 and P in Table1). At the end of 20 minutes, 1.4 g of triethanolamine (diluted with 1.4g of water) is introduced into the reactor, an aliquot sample is takenfrom the reactor in order to measure the softening point temperature. Atthis point, the resin is practically finished and does not advance morethan 3 to 4° C. over several hours. When the desired softening pointtemperature is reached, the heating is stopped and the resin can leavethe reactor for cooling, then analysis.

All the results are summarized in Table 1. TABLE 1 Molar ratio T1 T2/PMelt. pt. POP Stearic acid Ex. (MR) (° C.) (° C./bar) (° C.) (%) (%) 1130 150/0.4 0 2 0.83 150 150/0.4 96 2.8 0 +2 h: 101 2.3 3 0.83 150200/0.05* 104.5 1.4 0 +3 h: 109 0.4 4 0.60 150 150/0.4 59 14 0 5 0.88137 150/0.4 105 2.3 0 6 0.96 150 180/0.4 130 0.5 0 1.0 150 ** 110 1.3 0+1 h: 118 0.8 8 1.2 150 ** 140 0.2% 0 9 0.90 130 150/0.4 96 1.6% 5 2h/97 1.4% 10 0.93 130 150 95 1.1% 7.5 +2 h 98 0.95%  11 0.96 130 150 1020.7% 7.5 +1 h 106 0.7%*When the distillation of the residual PTOP is carried out, it isnecessary to operate at an elevated vacuum and temperature conditionsthat are otherwise undesirable from an industrial point of view.** The medium becomes too viscous and the step in a vacuum cannot becarried out without the risk of filling the reactor with the expandingresin. It is only possible to operate step 1 at atmospheric pressurethen transfer the resin.

Examples 12, 13 and 14 (Table 2)

A mixture is made with fusion between a resin sold by SchenectadyInternational, Inc. or CECA under the trade name R 7578P having asoftening point value between 120 and 140° C. and a free PTOP content ofless than 1% (novolac resin obtained by condensation of PTOP withformol) with different fatty acids indicated in Table 2. 120 g of resinare melted at 140° C., the fatty acid is then added, then the mixture isbrought to 180° C. in order to ensure a homogeneous mixture within oneto two hours. TABLE 2 Resin R 7578P Fatty acid Resin acc. to inventionPTOP ( ) Melt. pt. (%) PTOP ( ) Melt. Pt. Example % (° C.) Type % (° C.)12 0.6 125 stearic 5.2 0.6 110 13 0.6 125 stearic 8.0 0.6 103 14 0.6 123lauric 5 0.6 107

Example 15

Evaluation of the Tackifying Properties of the Resin From Example 11 incomparison to a commercial resin

Preparation of the Mixtures

The resins according to the invention are introduced into a mixture fora sidewall with a height of 4 parts per cent of elastomer (pce) withpolybutadiene (BR) base and polyisoprene (IR) according to the followingcomposition:

60 pce of BR 1.4 cis sold by Bayer under the name Buna CB 10,non-staining, with viscosity ML (1+4) of 42-53 at 100° C. and of whichthe amount of 1.4 cis is 96%,

40 pce of IR 1.4 cis sold by GoodYear under the name Natsyn 2200 withviscosity ML(1+4) of 70-90 at 100° C.,

60 pce of carbon black sold by Degussa under the name Corax N550, withaverage diameter 47 m.c. and weight per surface area of 43 m²/g,

5 pce of aromatic oil sold by BP under the name Enerdex 65 with density0.984 at 20° C. and with viscosity 25.5 cSt (mm²/s) at 100° C.,

5 pce stearic acid (activator),

5 pce zinc oxide,

2 pce anti-ozone and anti-aging protection agent(N-isopropyl-N′-phenyl-p-phenylene-diamine (IPPD)) sold by Bayer underthe name Vulkanox 4010 NA by Bayer,

2 pce of Vulkanox 4020LG, anti-ozone and anti-aging protection agentN-(1,3-dimethyl butyl)-N′-phenyl-p-phenylene-diamine (6PPD) from Bayer,

4 pce of tackifying resin from Example 11 or tackifyingalkylphenol/formol resin with melting point temperature of 102° C. soldby Schenectady International, Inc. or CECA under the trade name R 7521P,

1 pce insoluble sulfur (vulcanizing agent) sold by Flexys under the nameCrystex OT20, containing 78% total sulfur, and

1.5 pce of N-cyclohexyl-2-benzothiazyl sulfonamide (CBS)

The base mixtures or master mixtures (non-accelerated mixtures) areprepared in a Banbury type internal mixer with 390 cm³ capacity. It isimportant to note that the speed of the rotors, as well as the startingtemperature have been determined in such a way that the droppingtemperature of the mixture reaches at least 135° C. within a convenienttime (10 min). The gum and half the oil and carbon black are introducedat the same time, then the resin is ground a second time with the restof the oil and of the carbon black.

The mixtures are refrigerated immediately in a mixer with coldcylinders. After resting 24 h, the base mixtures are accelerated in theinternal mixer. The initial temperature of the chamber is 50° C. and thespeed of the rotors is 50 rpm. The mixing cycle is 6 minutes and thedropping is carried out at 100° C. to prevent any risk that the mixturewill burn. The forming is then carried out on cylinders at 70° C. Whenthe final mixtures are cooled, samples are cut off and stored protectedfrom light and in an atmosphere with controlled temperature (23±2° C.)and humidity (53±3% rel. hum.). Storage is carried out in Petri boxes;the samples are placed on sheets of paper since they adhere quickly andstrongly to glass.

Tack Measurement

This measurement is a measurement of traction on two disks of cruderubber in contact, and is carried out on an INSTRON dynamometer (model5565), equipped with the control software described below. The tackmeasurement assembly diagram is shown in FIG. 1.

Circular samples (diameter 18 mm, thickness 2 mm) are glued to steeldisks and put in place in the two mounting plates. The lower mountingplate is fastened and the upper is mobile and controlled by the controlsoftware. It lowers up to the application of a specific pressure Pc fora specific time tc, then it rises, measuring the force required to pullthe two samples apart.

The profile measurement carried out by the control software is made upof five ramps:

1^(st) ramp: Displacement of frame until Pc is reached (speed=5 mm/min),

2^(nd) ramp: Maintaining Pc for tc,

3^(rd) ramp: Raising the frame again at slow sped to return to acompression force zero. Variation in force of Pc+2N (speed=0.1 mm/min),

4^(th) ramp: Maintaining frame for 300 s, the rubber relaxes, the forceis returned to zero,

5^(th) ramp: Raising of the frame at constant speed set at 2 mm/min.

During the entire cycle, the computer registers the force as a functionof displacement, time, and tack measurement profile, as shown in FIG. 2.During the traction phase, the following significant values arerecorded: the maximum traction force, and the area under the curvegiving the force as a function of displacement, called adherence energy.

The conditions used for this manipulation are Pc=20 N and tc=20 x.

The tack measurements presented in Table 3 were carried out 1 day afteracceleration. TABLE 3 R 7521P Resin according to invention (Example 11)Tack (mJ) 68 ± 5 69 ± 5

The results show that the performance of this resin is at least as goodas the standard resin with a comparable softening point temperature,e.g. the resin R 7521P sold by Schenectady International, Inc. or CECAthat contains more than 3% free PTOP.

1. A novolac alkylphenol resin, comprising 2-20% by weight based on theweight of the alkylphenol, of at least one saturated or unsaturatedfatty acid, wherein the resin has a rate of residual alkylphenol of lessthan 2% and a softening point temperature between 85-105° C.
 2. Theresin of claim 1, wherein the rate of residual alkylphenol is less thanor equal to 1.5%.
 3. The resin of claim 2, wherein the rate of residualalkylphenol is less than or equal to 1%.
 4. The resin of claim 1,wherein the softening point temperature is between 95-105° C.
 5. Theresin of claim 1, wherein the amount of fatty acid ranges from 5-10% byweight, based on the weight of the alkylphenol.
 6. The resins of claim1, wherein the alkylphenols comprise phenols alkylated by a C₆-C₁₀hydrocarbon in the para position of the phenol group.
 7. The resin ofclaim 6, wherein the alkylphenol is para-tertiary octylphenol.
 8. Theresin of claim 1, wherein up to 30% of the total mass of the phenols ofthe resin is selected from the group consisting of phenol, resorcinol,cardanol, dialkylphenols, xylenols 2,4-diterioctylphenol,2,6-diterioctylphenol, and combinations thereof.
 9. The resins of claim1, wherein the fatty acid is a saturated mono-carboxylic acid or amono-olefinic acid having at least 8 carbon atoms.
 10. The resin ofclaim 9, wherein the fatty acid is a saturated fatty acids having 8 to32 carbon atoms, or a synthetic or natural mixture of fatty acidsobtained by saponification of vegetable oils or animal fats.
 11. Theresin of claim 10, wherein the fatty acid is stearic acid.
 12. A processfor preparing a novolac alkylphenol resin, comprising: (a) reacting analkylphenol with an aldehyde to form a first resin, wherein the molarratio of the alkylphenol:aldehyde is at least 0.9:1.0, and (b) mixingthe first resin with at least one saturated or unsaturated fatty acid ina melted state, to form a novolac alkylphenol resin, wherein the novolacalkylphenol resin has a residual alkylphenol of less than 2% and asoftening point temperature between 85-105° C.
 13. The method of claim12, wherein the rate of residual alkylphenol is less than or equal to1.5%.
 14. The method of claim 13, wherein the rate of residualalkylphenol is less than or equal to 1%.
 15. The method of claim 12,wherein the softening point temperature is between 95-105° C.
 16. Themethod of claim 12, wherein the amount of fatty acid ranges from 2-20%by weight, based on the weight of the alkylphenol.
 17. The method ofclaim 16, wherein the amount of fatty acid ranges from 5-10% by weight,based on the weight of the alkylphenol.
 18. The process of claim 12,wherein the aldehyde comprises formol.
 19. A process for the preparing anovolac alkylphenol resin, comprising condensing an aldehyde and analkylphenol in the presence of at least one saturated or unsaturatedfatty acid at a temperature of less than or equal to 200° C., to form anovolac alkylphenol resin, wherein the novolac alkylphenol resin has aresidual alkylphenol of less than 2% and a softening point temperaturebetween 85-105° C.
 20. The method of claim 19, wherein the rate ofresidual alkylphenol is less than or equal to 1.5%.
 21. The method ofclaim 20, wherein the rate of residual alkylphenol is less than or equalto 1%.
 22. The method of claim 19, wherein the softening pointtemperature is between 95-105° C.
 23. The method of claim 19, whereinthe amount of fatty acid ranges from 2-20% by weight, based on theweight of the alkylphenol.
 24. The method of claim 23, wherein theamount of fatty acid ranges from 5-10% by weight, based on the weight ofthe alkylphenol.
 25. The process of claim 19, wherein the aldehydecomprises formol.
 26. The process of claim 19, wherein the condensingtemperature is less than or equal to 180° C.
 27. The process of claim26, wherein the temperature is less than or equal to 160° C.
 28. Theprocess of claim 19, wherein the process is conducted in a batch orcontinuous process.
 29. A method of using the resin of claim 1 as atackifying resin in a rubber-based formulation.
 30. The method of claim29, wherein the use is in the area of tire manufacturing.
 31. A methodof using the resin of claim 1 as a reinforcing resin in a rubber-basedformulation.
 32. The method of claim 31, wherein the use is in the areaof tire manufacturing.